Modular Modeling SystemUser Group Newsletter

(A B&W Nuclear Service Company Software Bulletin)

January 1990 Vol. 4 No. 1

B&W HAS A NEW NAME

As you might have noticed from ourlogo above, we have changed ourname. On November 1, 1989Babcock & Wilcox and Framatomebegan a new partnership, the B&WNuclear Service Company (BWNS).

•Framatome is a key participant inFrance's successful nuclear programand has manufactured 66 standardizedpressurized water reactors.

We are looking forward to this newpartnership and believe it will offerthe MMS User Group newopportunities to expand itsmembership.

Insofar as current MMS licenseagreements are concerned, there willbe no changes other than to transferthem to BWNS. The MMS willcontinue to grow, as in the past, andit is our intent to maintain and improvethe MMS as directed by the UserGroup.

CURRENT MMS USERS

The current register of organizationsusing the MMS includes:

- Nineteen (19) commercial members- Ten (10) universities

(See USERS, page 6)

USER GROUP MEETING

Plans for our next MMS User Groupmeeting are close to being finalized.

The meeting will be held at the HyattRegency Chicago hotel on Thursday,April 26, 1990 in Chicago, Illinoisfollowing the American PowerConference which will be held at theHyatt Regency in Chicago on April23,24,25.

We will send you more detailedinformation on both meetings in thenear future.

Information on available suites andtheir cost can be obtained bycontacting the Hyatt RegencyChicago directly:

Hyatt Regency ChicagoReservation Manager151 East Wacker DriveChicago, IL 60601(312) 565-1234, Ext. 1432

The American Power Conferencecovers electrical, mechanical, nuclear,industrial, cost, water technology,civil, hydro and education disciplines.We believe that many MMS users willbe interested in attending the APC inconjunction with the MMS UserGroup meeting.

We anticipate an informative andproductive User Group meeting andrecommend that you make your plansto attend now.

NEWSLETTER RESTARTED

The last MMS newsletter waspublished in July, 1987. The mainreason it was discontinued was thatit became increasingly difficult toobtain articles from our members.

We think the newsletter is anexcellent way for members to sharetheir MMS experiences and weencourage each of you to send usarticles for inclusion in future editions.

The newsletter will be publishedseveral times each year and we inviteyour comments as to what you wouldlike to see included.

MMS VITAL STATISTICS

Proj. Mgr.: H.C. (Pete) CheatwoodPhone: (804) 385-2442

Tech. Supr: G.F. (Greg) MalanPhone: (804) 385-3283

Tech. Cnslt: R.B. (Bob) BrownellPhone: (804) 385-2779

Tech. Cnslt: N.S. (Norm) YeePhone: (804) 385-3305

All of the above can be reached viafax number (804) 385-3663.

FOSSIL PLANT MODEL AT DETROIT EDISON

The principal components of a660MW B&W coal fired unit havebeen modeled at Detroit Edison usingMMS. Initial work involved modelingthe process and controls in fivesubsystems and tuning eachindependently. Three engineers havebeen involved about half time for ayear. MMS-EASE+ was used foreach subsystem setup. Most datawas obtained from plant designdrawings and documents but somedata was available from a steadystate model of the boiler.

The first subsystem was thesuperheaters and portions of thereheater with detailed multi-loopsuperheat attemperation control. Thedrum outlet and turbine inlet wereboundary conditions. A portion ofthe reheat tube banks was includedto connect the gas path. The 38state subsystem was usedindependently to study and confirmthe attemperation control stabilityduring transition between valve banksand at the saturation point.

The drum and furnace submodelconsisted of the DRUMNC modulewith pipes at the water inlet andsteam outlet. A three element level-feedwater control was setup. Gainshave not been available from theplant, therefore data from previousMMS papers and tuning experiencewere used to adjust the system. Themodel was calibrated using designdata and compared favorably withexception of the gas outlettemperature. The model predicted ahigher gas temperature than expectedand measured in the plant. Howeverthis may be explained since thefurnace module overlaps the platensuperheater and does not use energystreams and therefore outlet gas mustcontain and transfer the energy to theplaten.

The reheaters and economizerssubsystem completed the gas flowpath and enabled calibration of the

five equivalent tube banks and tuningof the reheat temperature control. Asignificant problem encountered wasan error in the heat transfercalculation for the economizer.Several iterations of coefficientadjustment resulted in goodagreement with the inhouse steadystate model. The PI temperaturecontrol included appropriate scalingof limits and was tuned for a stepresponse resulting in slight overshoot.

The turbine system primarilyprogramed by Zuwei He, a visitingChinese professor, modeled the HP,IP, and LPturbines and condenser.

Since the HP turbine doesn't haveimpulse blading, TURBLP was usedfor modeling all the turbines. Tomake this subsystem independent apipe with heat transfer was used torepresent the reheat and functionalrelationships were used to representthe boundary conditions at theextracting line terminations. Afterfixing three small errors in theturbinecoding, excellent agreementwas obtained between the'model anddesign data down to 75 percent load.Turbine step response and condenserparameterization sensitivity studieswere conducted.

(See DETROIT, page 5)

DETROIT EDISONBELLE RIVER PLANT MODEL

PENN STATE'S USE OF MMS HELPS OBTAIN 2 MAJOR GRANTS

The Nuclear Engineering Departmentat Penn State has been using theMMS since 1985 for graduateresearch and undergraduateinstruction. Six masters of scienceprojects have been conducted withthe MMS as the primary tool. Inaddition, the MMS has been adaptedfor real time simulation using the IBMAdvanced Control System Software.This experience was an importantfactor in successfully obtaining twonew major government researchgrants.

The two new grants, one from theNational Science Foundation (NSF)and the other from the Department ofEnergy (DOE), are very much relatedand are being used to establish whatwe call Intelligent Distributed Controlsresearch. The NSF grant wasawarded in July (89) and will providea state-of-the-art microprocessorbased control system. The BaileyNETWORK 90-system will contain a386 based Engineering Work Stationwhich is used to configure andprogram controllers (see figure). TheBailey Multifunction controller (MFC)can accommodate 5000 lines of userdefined C code for execution as partof a control strategy involvingstandard control blocks and thereal-time executive module of thecontroller. The research using thisequipment will explore the addition ofexpert systems technology and otherArtificial Intelligence applications aspart of control. A major activity willbe to interface the microprocessorbased control system with othercomputer networks at Penn State.These interfaces through the BaileyComputer Interface Units (ClUs) willpermit the output of mainframe basedsimulations to drive the controllers.Access to controller operations willalso be made available to higher

level diagnostic and control functionsexecuting in an ETHERNET networkof UNIX based workstations. Deliveryof the Bailey system is expected inJanuary.

The 2nd new major grant will involvePenn State in the development of aprototype demonstration of IntelligentDistributed control at the ExperimentalBreeder Reactor in Idaho. The EBR-IIplant is a small but complete powerplant that supplies 20 MWe to thegrid and the controls demonstrationwill be conducted on the EBR-IIsteam cycle power plant. The steamcycle at EBR-II is similar to mostthermal power plant and in particularresembles a fossil fueled plant in thatit has a natural circulation drum boilerand superheater system that supplieshigh quality steam to the turbine.Instead of a combustion furnaceheating the water and steam, liquidsodium is the heat source. Despitemost peoples' misgivings at usingsodium in a steam generationsystem, EBR-II has successfullydemonstrated this technology sincethe 1960s. Big pluses for the use ofsodium are that it is not required tobe pressurized because of its highboiling point and it is not corrosive tostainless steels. The EBR-II steamboiler also uses a double wall tubedesign with separate tubesheets forthe water and sodium sides. Thesystem is -carefully monitored forleaks and special provisions forquickly draining the water areprovided. Other features of theEBR-II steam system include aturbine, blowdown, condensate, andfeedwater system.

There are three closed feedwaterheaters and a deaerating heater.Most of the original analog controlsystems have already been replaced

with Bailey NETWORK 90 controllerssimilar to those being obtained atPenn State through the NSF grant.

The DOE intelligent distributedcontrols demonstration is organizedas a three year project and began inSeptember of 1989. The first year'sactivities are: 1) develop a simulationof the EBR-II steam cycle powerplant, 2) develop a diagnostic systemfor the steam cycle, and 3) test thediagnostic on a real-time simulation.The first year milestone is todemonstrate the diagnostic systemoperating in a SUN workstationinterfaced to live plant data at EBR-II.The EBR-II steam cycle simulation isof course being developed using theMMS and is the masters degreeproject of David Ruhl. During the lastspring semester, Dave completed asimulation of the EBR-II feedwatersystem using the standard modulesavailable in the MMS library. Davewas fortunate enough to be hired asa summer student at EBR-II where hegot to see the plant first-hand andcollected data to complete thesimulation project. Dave is nowworking on creating modules for theEBR-II steam generators which arebeing based on the correspondingMMS fossil library modules.

The development of a diagnosticsystem for the steam cycle will useDISYS2, diagnostic and controlguidance expert system. DISYS wasoriginally developed at Westinghousefor DOE. The first year activity forthe new DOE project is very similarto that performed in a Penn StateDOE project recently completed inMay of 19893. That project convertedDISYS to the C language andcompleted implementation of the

(See PENN, page 4)

(PENN - cont. from page 3)

diagnostic for the Argon CoolingSystem of fuel handling operations at

EBR-ll. That diagnostic system wasalso tested on a real-time simulationusing the MMS and was the mastersdegree project of John Carper.Over the summer and continuing tothe end of 1989, the DISYSdevelopment was extended toprovide a graphical operator interfacein the UNIX X-Windows environmentof SUN computers (see slide). (Asmight be expected, the Bailey 386based engineering workstation is alsobeing equipped with UNIX andX-Windows software.)

The 2nd and 3rd years of the DOEprogram have been proposed andaccepted in principle but continuationproposals are required for each year.The second year (beginningSeptember 1990) will develop theimplementation of the DISYSdiagnostic system in a distributedcomputer system. The diagnosticsystem developed for operation in asingle SUN computer at the end ofthe first year will be distributedbetween Bailey microprocessor-basedcontrollers and the SUN computernetwork. Again, a major activity willbe simulation testing of thedistributed diagnostic system at PennState using the equipment madeavailable by the NSF grant. The 3rdyear activity will examine closing thecontrol loop to automatically effectchanges in control based on thediagnosed state of the system,Intelligent Distributed Control.Intelligent Distributed Controlsresearch at Penn State is aninterdisciplinary project involvingElectrical, Mechanical, and IndustrialEngineering, as well as NuclearEngineering. Bob Edwards, who hasattended many of the MMS usergroup meetings, is a full timeresearch assistant and PhD candidatein Nuclear Engineering. Dr. Klevans,

Nuclear Engineering Departmenthead, is the principal investigator forthe DOE project. Dr. Kenney,Professor of Nuclear Engineering, isthe principal investigator for the NSFgrant. Dr. Kenney teachesinstrumentation laboratories and thereactor control course. M.A. Schultz,professor emeritus and author of thefirst book on reactor control, will bean active consultant to the DOEproject. Schultz has campaignedheav i l y f o r d i s t r i b u t e dmicroprocessor-based control as ameans to greatly simplify futurepower plant control rooms. Dr.Kwang Y. Lee of the ElectricalEngineering department teachespower systems and the EE controlsequence of courses includingoptimal control. Dr. Asok Ray ofMechanical Engineering conductsresearch in distributed computer andcommunication systems inmanufacturing. Dr. Soundar Kumaraof Industrial Engineering is involvedwith Artificial Intelligence applicationsin manufacturing with special interestin qualitative reasoning.

The MMS is an important power plantsimulation tool that will be used inthese new research projects. If youwould like to learn more aboutIntelligent Controls Research and useof MMS at Penn. State, pleasecontact Bob Edwards.

With the MMS experience that hasbeen established at Penn State, thepossibility of conducting a MMS shortcourse for industry participants isunder consideration. Penn State isbest equipped to conduct courses forIBM mainframe computer users andthe two weeks prior to Memorial dayor the middle two weeks of August(between semesters) is the best timeto guarantee availability of equipmentand full attention of facultyinstructors. It may also be possibleto orient an MMS short course to aVAX computer environment if thatwould be the preference of industry

participants. In order to schedule thenecessary resources for a course inMay, a definite decision will have tobe made by Jan. 31, 1990. If youhave an interest or any questionsplease contact Pete Cheatwood orBob Edwards at Penn State.

References:

1) R.M. Edwards and G.E. Robinson,"Real-time Modeling and ControlsAnalysis Using the MMS and theIBM Advanced Control System(ACS)," EPR11988 Conference onPower Plant Training Simulatorsand Modeling, Charlotte, NorthCarolina, June 15-17, 1988.

2) R.M. Edwards, J.J. Carper, R.W.Lindsay, and G.E. Robinson,"Real-time Testing of a Diagnosticand Control Guidance ExpertSystem", Proceedings of theSeventh Power Plant Dynamics,Control, and Testing Symposium,Knoxville, Tennessee, May 15-18,1989.

3) Robert M. Edwards, John J.Carper, and Gordon Robinson,"Final Report, Testing andInstallation of the DISYS DiagnosticSystem on the EBR-ll ArgonCooling System," A project underDOE contract No. 31 -109-ENG-38,June 30, 1989.

4) Robert M. Edwards, K.Y. Lee, S.Kumara, and S.H. Levine, "AnIntegrated Real-time DiagnosticConcept Using Expert Systems,Qualitative Reasoning andQuantitative Analysis," An invitedpaper and presentation at theU.S.-Korea Seminar on Applicationof Expert Systems to PowerSystems and Industries, Seoul,Korea, August 13-18, 1989.

R.M. EdwardsPennsylvania State University

231 Sackett BuildingUniversity Park, PA 16802

(DETROIT, cont. from page 2)

The feedwater subsystem is thelargest at 62 states. It includesseven equivalent banks of heaterswith controls and four sets of pumps.The system has feedforward drains,that is a portion of heater drains ispumped into the condensate systemby drains pumps. Because of limiteddesign information and in the interestof time, three dummy controls wereadded to force some conductancesand pump speeds to provide thedesign flow and pressure profiles.Design tuning parameters resulted ingood level response for each heater.

Recently these submodels have beenmerged into two large models. Oneconsists of all but the feedwatersubsystem. This 88 state modelrepresents the boiler from fuel inputto the gas outlet at the air heatersplus the turbine system. After theinitial merge, numerous computerruns were necessary to establish asteady state condition. Apparentinteraction between the feedwatercontrol and the superheat controlsystems has made the modelsurprisingly oscillatory. Althoughsome complaints of oscillations werereported during plant startup, wehave not been able to obtain data toconfirm or compare against. Themodel has been calibrated againstdesign and field test data and majorparameters compared very favorablyafter slagging coefficients wereadjusted. For mild transients themodel runs efficiently.

A 4000 second model run requiresonly 20 seconds on an Amdhalcomputer. Presently the coordinatedunit control scheme is being addedto the model and data is beingobtained to compare the modelresponse to a ramp down field testwhich has been conducted.

The second large model consists ofthe merged feedwater and turbinesubmodels. This 85 state model ranto a steady state condition fairlyeasily considering the numerous

common extraction lines involved,and compared closely with designdata. Presently thismodel is beingenhanced to include more detail inthe condenser level control andcooling water dynamics. Plantengineers have requested aprediction of the speed of impact onthe system to the loss of a circulationwater pump and how much time anoperator will have to startup anotherpump. During winter, operation withonly one of three pumps is beingconsidered. The ultimate goal is tocombine the two larger models.Considering the mutual turbine, thecomplete model will have 150 states.

Regardless, we expect continueduseof our fossil model andsubmodels to solve some of thenagging problems and questions atthe plant and be an immediatelyavailable tool tosolve the emergencysituations that invariably occur atoperation plants.

Chuck Amdt / Terri OrloffDetroit-Edison

The BWNS

MMS Team

Wishes for you

a

Prosperous

and

Happy New Year

- TECH TIPS -ALGEBRAIC

LOOPS

Occasionally, when setting up simplecontrol loops or dummy parameteradjustment loops, we unknowingly setup a subset of equations that form analgebraic loop, that is, a set that boilsdown to Y=f(y). ACSL cannotnormally handle these because itsorts the input equations and "everyvalue is assumed calculable on theoutputs of the integrator: (and storageelements). ACSL tells us there areseveral methods to eliminate theseloops, namely: 1) algebraicallymanipulate the equations so that thevariable can be calculated directly, 2)use a Procedure block so the loop isnot sorted, or 3) use the IMPLoperator which separately used theNewton-Raphson method tonumerically solve the loop duringevery iteration.

These could be good solutions,however we find that frequently inusing MMS, more realistic modelsnormally eliminate algebraic loops.For instance in simple control loopsinvariably an actuator and/ortransducer is in the loop.Transducers are often represented bya REALPL which breaks the loop.Actuator response times range formseconds tominutes and transducerequivalent time constants range fromfractions of a second or seconds forpressure transducers to severalseconds for RTDs. Probably thetemperature -transducer well will bethe most significant lag especiallywhere it is massive to protect theelement from abrasion eg. coal milloutlet (20 seconds). Forattemperation, some recent spec wereviewed showed measuring timeconstants of 8 seconds.

Another encounter with the algebraicproblem occurred with functionalrelationshipsfor boundary conditions.In that case a REALPL was added tonot only break the loop but also

(See TIPS, page 6)

(TIPS, cont. from page 5)

make the termination response morerealistic since in the case sited, thepressure would not have instantlychanged due to flow change. Sincethe response of the termination wasnot known, the time constant wastemporarily set to a value smallerthan that of the predominant ones inthe model so as to not significantlyinfluence the dynamics.

Dummy loops to initially adjustparameters for calibration arenormally setup in our work to includea REALPL. Besides eliminating apossible algebraic loop, it slows thecorrective action and more graduallyforces the model into calibrationpreventing other possible numericalproblems.

In general, we find more realisticmodels produce less problems.Evidently Mother Nature must havesolved these problems long ago!!!

Chuck ArndtDetroit Edison

MMS TRAINING OFFER

BWNS is pleased to offer to anyMMS User Group memberorganization, an economical two daytraining session on MMS.We will send an MMS expert to yoursite to train your personnel on anyaspect of MMS.The only expense to you will be thetravel and living expense of ourinstructor.

We are making this offer because wewant to help you utilize the fullcapabilities of the MMS and becausewe believe the training can be mademore effective by tailoring ourcourses to your unique requirements.

Contact H.C. Cheatwood to schedulethis training for your personnel.

NEW PRODUCTPower Master ™

BWNS has developed, and ismarketing, a personal computerbased dynamic simulation for B&Wdesigned nuclear power plants andtheir control systems.

Power Master provides near real-timesimulation, interactive graphicsdisplays of the plant dynamicvariables with the ability to easilymodify the plant parameters on-line.

We used a B&W NSS 177 PWR asthe plant model and the B&WIntegrated Control System (ICS) asthe control system model.

Power Master is being offered toMMS User Group members at areduced price. If you would like toreceive more information on PowerMaster, contact H.C. Cheatwood.

1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.

(USERS, cont. from page 1)

Bechtel Power Corp.Chiyoda Corporation, Ltd.Chongqing UniversityChubu Electric Power Co.Cornell UniversityDelft UniversityDetroit EdisonDuke Power Co.Empresarios Agrupados SAGent UniversityIceland UniversityKarlstad UniversityKemaLaborelecNiagara Mohawk Power Corp.Oak Ridge National Lab.Philadelphia Electric Co.Pennsylvania State Univ.Public Service Elect. & GasSan Diego Gas & ElectricStork BoilersStuttgart UniversitySwedish State Power BoardSydkraft ABSouthern Cal. Edison Corp.Tennessee Technological Univ.Texas UniversityToledo Edison Co.Tennessee Valley Authority

MMS UTILITIES

SCAN - On September 11, 1989, wesent all MMS installations a diskettecontaining our new SCAN pre-processor software that can be usedto convert MMS/ACSL model andcommand files from SI units to USunits (MMS uses US units).

We are integrating, into the MMSsoftware, the ability to use either SIor US units. This project should becompleted by the middle of 1990.

If you have not yet received a copyof SCAN, please contact the MMScoordinator for your company.

SPLIT - If you have ever received aMicrosoft FORTRAN compilermessage indicating that the ACSLtranslated FORTRAN file is too large,you should try the MMS utilityprogram SPLIT. SPLIT will divide theACSL generated ZZDERV.FORsubroutine into smaller subroutineswhich can be compiled and linked togenerate an executable file.

CRITER The CRITER programprocesses the Jacobians printed byACSL and recommends error criteriaappropriate to the precision of thefloating point calculations of the hostcomputer. MMS users haveobserved that some MMS models runmore efficiently on computers whichcompute with more precision. Forexample, the BEXR MMS sampleproblem runs on the CDC mainframe(which has 60 bits of precision) buttakes an excessive number ofderivative evaluations on the IBMmainframe (which has only 32 bits ofprecision). CRITER is a programautomating the procedure describedin the report to MMS users,"Improving Numerical Efficiency ofMMS on IBM Mainframes", May 1988.The procedure described in thereport also applies to other 32-bitcomputer systems such as IBM PCcompatibles. The procedure isexperimental and has beendemonstrated to work with severaltroublesome problems.